An auxiliary view is an orthographic view that is projected onto any plane other than the frontal, horizontal, or profile plane. An auxiliary view is not one of the six principal views. To show the true size and shape of surface ABCD, an auxiliary view can be created by positioning a line of sight perpendicular to the inclined plane, then constructing the new view.
Trang 1
Auxiliary Views
Trang 2
Motivation
One view of the surface seen on edge
Two views seen as a foreshortened
(i.e., not true size) surface
Multiview drawing set of an inclined
surface shows:
Sometimes need a view of inclined surface that shows its true size and shape
Trang 3
From Descriptive Geometry
Line of sight is normal to the face, or,
equivalently,
View plane is parallel to the face
True size and shape of a planar face (or true length of a line) can only be
represented in an orthographic projection if:
Trang 4
Definitions
An auxiliary view is an orthographic
view that is projected onto any plane
other than one of the principal planes
A primary auxiliary view is an auxiliary
view projected from one of the six
principal views
Used to find true size of an inclined surface
A secondary auxiliary view is a view
projected from a primary auxiliary view
Used to find true size of an oblique surface
Trang 5
Auxiliary View Projection Theory 1
Object with inclined surface placed inside glass box
Additional plane added to glass box parallel to inclined
surface Inclined surface projected onto inclined plane
Trang 6
Auxiliary View Projection Theory 2
Inclined projection plane hinged to
principal projection plane (Horizontal, Frontal, Profile) that shows inclined
surface as an edge
Trang 7
Auxiliary View Projection Theory 3
Views unfolded auxiliary view shows true size and shape
of inclined surface Distance from hinge
to edge of inclined surface same for all views, principal or auxiliary
Convention is to only show inclined surface in an
auxiliary view
Trang 8
Auxiliary Views: 3 Cases
Depending upon
where the inclined
surface appears
on edge, primary
auxiliary views can
be projected from
either the:
Trang 9Trang 10
Auxiliary Views
Over and Out